Diversity of Vibrios in the Coral Reef Ecosystem of Ishigaki Island, Japan [an abstract of dissertation and a summary of dissertation review]Diversity of Vibrios in the Coral Reef Ecosystem of Ishigaki Island, Japan [an abstract of dissertation and a summary of dissertation review]石垣島周辺海域のサンゴ生態系におけるビブリオの多様性 [論文内容及び審査の要旨]